In order to replace a defective unit or recover an expensive component from an otherwise operable circuit, it is desirable to easily insert and remove various units from a circuit board. Expensive and space consuming sockets which usually require plated through holes are often used to facilitate location and removal of particular components. On current chip carriers, having approximately 0.050" centers tolerances on the carrier and socket are sufficient to accommodate socketing. On the integrated circuit carriers (chip carriers) with leads on 0.025" centers, there are few sockets on the market which can satisfactorily perform such location and removal of components. These sockets require very tight tolerance carriers and must sometimes be optically aligned. Unfortunately, it is very difficult to obtain sockets which will contact high density circuits and many new circuits today are surface mounted and have no plated through holes to accept normally leaded devices.
The current technology maintains the integrated circuits on chips on substrates of either ceramic, laminate or plastic and solders these carriers to the circuit boards directly or through resilient leads. As board spacing becomes closer, i.e., less than 0.050 inches on centers of the contacts, soldering components become difficult as individual leads become misaligned and solder bridging becomes a serious problem. Also, the heat of soldering can ruin temperature sensitive parts on printed circuit boards. As board spacing is being reduced to 0.025" centers and chip carriers with centers of 0.012" are in the design stages, the soldering problem becomes more acute and must be addressed to maintain pace with the increasing efficiency of the electronic industries.
Because of these and other problems associated with the prior art, it is an object of the present chip carrier to provide a device requiring minimal board space.
Another object of the invention is to accommodate chip carrier contact spacing closer than on 0.025 inch centers.
A further object of the chip carrier is to provide ease of field replacement at a low cost.
Additionally, an object of the invention is the ability to manufacture and test such chip carriers automatically.